Development of Standards for Radiopharmaceutical Doses in Pediatric Nuclear Medicine Recommended

Radiopharmaceutical guidelines should be established for consistent dosage standards, according to a recent report.

Results of a recent survey of 13 pediatric hospitals in North America show a lack of universally applied standards for administering radiopharmaceutical doses to children undergoing nuclear medicine examinations, according to an article in the June 2008 issue of The Journal of Nuclear Medicine (JNM).

"Modern nuclear medicine procedures are sensitive, minimally invasive, painless, and safe and thus well suited for the evaluation of pediatric patients. They provide a wealth of unique and useful information that can be used to diagnose and treat many diseases of childhood,” said S. Ted Treves, M.D., chief of the division of nuclear medicine at Children's Hospital Boston (MA, USA) and professor of radiology at Harvard Medical School (Cambridge, MA, UDS).

In nuclear medicine, there are well-established guidelines for administering radiopharmaceutical doses for adults. However, Dr. Treves stated, "At this time, the majority of radiopharmaceutical package inserts do not provide guidance on pediatric doses. In imaging children, physicians typically base dosages on the patient's body weight, the nature and the type of problem being investigated, the equipment available, and their own experience. This has led to the variations in dosage that currently exist.”

This approach, however, may result in the smallest patients receiving a dose that is too small to produce adequate results. Furthermore, according to experts, radiopharmaceuticals are handled differently in infants and young children. For example, circulation time in newborns is faster than it is in adult patients. These and other kinetic and metabolic differences can make a difference in the doses children require. The wide range of disorders, body sizes, stages of development, and level of patient cooperation require customized approaches to dosimety and to the various imaging techniques that are used in making a diagnosis.

"This survey identifies a very important question: What are the lowest radiopharmaceutical dosage levels that are compatible with quality imaging in children?” asked Dr. Michael Gelfand, M.D., president of the Society of Nuclear Medicine's (SNM; Reston, VA, USA) Pediatric Imaging Council. "Over the last few years, the imaging community successfully tackled the problem of computed tomography [CT] absorbed radiation doses that, in many cases, were higher than required for quality imaging. Although nuclear medicine scans are performed less frequently than CT scans and generally involve much less radiation, this report has identified a question that needs attention.”

In an effort to document pediatric radiopharmaceutical doses among a group of pediatric hospitals, Dr. Treves and his coauthors designed a survey consisting of 16 pediatric nuclear medicine examinations. Survey participants were asked to report the minimum and maximum administered activities for each exam as well as the administration schedule based on body weight. From these data, the investigators computed minimum, maximum, median, and mean values for each procedure, which confirmed what they had long suspected: Among the institutions surveyed, the administered doses varied widely, with the greatest disparity noted in the smallest patients for levels of minimum total administered activity.

The study authors recommend establishing guidelines that balance the need for high-quality image resolution and low radiation exposure with each child's unique profile. The researchers reported that their findings suggest a definite need to achieve some level of standardization by reaching a wider consensus on pediatric radiopharmaceutical dosimetry. They hope to stimulate a dialogue within the pediatric nuclear medicine community that will ultimately lead to the establishment of guidelines for administered radiopharmaceutical doses in children that rely on the most current instrumentation, imaging processing techniques, and computer technologies.

Other recommendations include utilizing new image-processing techniques that have emerged in the last few years that offer advantages over older methods by generating images of vastly improved quality that provide diagnostic information with lower administered radiopharmaceutical doses. The investigators are presently applying these new techniques to a variety of tests.


Related Links:
Harvard Medical School
Society of Nuclear Medicine